Regulated strobe for camera with sixth flash inhibit

Abstract

An electronic flash accessory is provided for a camera of the type having a flash socket assembly adapted for receipt of a conventional multiple flash bulb array together with circuitry for sampling the terminals of the flash socket which are adapted to connect to the last flash bulb scheduled to be fired in the array and for providing a signal which operates to inhibit camera operation when the sampled impedance of the last flash bulb scheduled to be fired is substantially different from the impedance of an unfired non-defunct flash bulb. The electronic flash accessory includes circuitry responsive to a predetermined event relative to the readying of the flash accessory in expectation of the commencement of a photographic exposure cycle involving an artificially illuminated subject for simulating the impedance of an unfired non-defunct flash bulb in order to enable the camera to automatically perform a photographic exposure cycle upon actuation by the camera operator.

What is claimed is: 
     
       1. An electronic flash accessory for a camera of the type having a flash socket adapted for receipt of at least one conventional flash bulb together with means for sensing the terminals of the flash socket which are adapted to connect to the flash bulb to provide a signal which operates to inhibit camera operation when the impedance of the flash bulb is substantially different from the impedance of an unfired non-defunct flash bulb and means for providing a trigger signal, said flash accessory comprising: a housing;   a storage capacitor;   a discharge tube;   means responsive to an applied voltage for charging said capacitor;   means responsive to the trigger signal for discharging said capacitor through said discharge tube to produce an illuminating flash of light;   connector means for electrically connecting said discharging means to the camera flash socket, said connector means terminating in at least two terminal elements configured to connect respectively to those terminals of the flash socket which are adapted to connect to the flash bulb, said terminal elements thereby accommodating receipt of the trigger signal from the camera; and   means normally operative for providing an impedance characteristic across said connector means terminal elements substantially different from the impedance of an unfired non-defunct flash bulb thereby inhibiting camera operation upon connection of said discharging means to the camera socket, said impedance providing means being responsive to a predetermined event relative to the readying of said flash accessory in exception of the commencement of a photographic exposure cycle involving an artificially illuminated subject, for simulating the impedance of an unfired non-defunct flash bulb across said connector means terminal elements thereby enabling the camera to perform a photographic exposure cycle involving an artificially illuminated subject upon actuation by the camera operator.   
     
     
       2. An electronic flash accessory for a camera of the type having a flash socket assembly adapted for receipt of a conventional multiple flash bulb array together with means for sensing the terminals of the flash socket which are adapted to connect to the last flash bulb scheduled to be fired in the array and for providing a signal which operates to inhibit camera operation when the impedance of the last flash bulb scheduled to be fired is substantially different from the impedance of an unfired non-defunct flash bulb and means for providing a trigger signal, said flash accessory comprising: a housing;   a storage capacitor;   a discharge tube;   means responsive to an applied voltage for charging said capacitor;   means responsive to the trigger signal for discharging said capacitor through said discharge tube to produce an illuminating flash of light;   connector means for electrically connecting said discharge means to the camera flash socket, said connector means terminating in at least two terminal elements configured to connect respectively to those terminals of the flash socket which are adapted to connect to the last flash bulb in the array scheduled to be fired, said terminal elements thereby receiving the trigger signal from the camera; and   means normally operative for providing an impedance characteristic across said connector means terminal elements substantially different from the impedance of an unfired non-defunct flash bulb thereby inhibiting camera operation upon connection of said discharging means to the camera socket, said impedance providing means being responsive to a predetermined event relative to the readying of said flash accessory in expectation of the commencement of a photographic exposure cycle involving an artificially illuminated subject, for simulating the impedance of an unfired non-defunct flash bulb across said connector means terminal elements thereby enabling said camera to perform a photographic exposure cycle involving an artificially illuminated subject upon actuation by the camera operator.   
     
     
       3. The electronic flash accessory of claim 1 whrein said impedance characteristic providing means includes means for simulating the impedance of an unfired non-defunct flash bulb in series connection with normally open switch means which are arranged to close in response to said predetermined event relative to the readying of said flash accessory. 
     
     
       4. The electronic flash accessory of claim 3 wherein said switch means is arranged to close synchronously with the application of the applied voltage to said capacitor charging means. 
     
     
       5. The electronic flash accessory of claim 3 wherein said switch means is arranged to close synchronously with the charge on said capacitor reading a predetermined value.